Effects of vitamin E deficiency on the functions of splenic lymphocytes and alveolar macrophages

This study has been done to determine the effect of vitamin E deficiency on the functions of splenic lymphocytes and alveolar macrophages (AM) in rats. Vitamin E deficiency did not cause any changes of body weight, spleen and thymus weights, and numbers of splenocytes and AM compared with those of control rats. And also, we could not find any significant changes of lymphocyte responses to mitogens (PHA, Con A, and LPS) and natural killer cell (NK) activity except for AM function in vitamin E-deficient rats. In vitamin E-deficient rats, AM showed a higher phagocytosis than that of control rats. After in vitro treatment with a macrophage-activating factor (MAF) for 4 h at 37 degrees C, AM from control rats showed a greater enhancement (167%) of phagocytic activity compared with that of AM from vitamin E-deficient rats. When the effect of MAF prepared from splenic lymphocytes of rats from control or vitamin E-deficient rats on phagocytosis of AM was studied, MAF from control rats showed an about 150% increase of phagocytic activity in a 1/250 dilution of MAF. However, MAF from vitamin E-deficient group had almost no effect on phagocytosis of AM in the same dilution of MAF as control rats. These results may suggest that vitamin E deficiency induces the higher phagocytic function of AM responsible for host defense in the lung, but their enhancement is not due to the activation by MAF from lymphocytes.     

Phagocytosis of alveolar macrophages of pyridoxine-deficient rats

We measured phagocytosis of opsonized sheep red blood cells by alveolar macrophages (AM) of rats fed a diet with or without pyridoxine for 4 weeks. In pyridoxine-deficient (DEF) and pair-fed control (PF) groups AM showed a higher degree of phagocytosis than those of rats in the ad libitum-fed control (AL) group. After in vitro treatment with a macrophage-activating factor (MAF), such as lymphokines, for 4 hours at 37 degrees C, AM from the PF and AL groups showed a greater enhancement of phagocytic activity than AM from the DEF group, which was slightly enhanced. When the effect of MAF prepared from splenic cells of rats of the PF or DEF groups on the phagocytosis of AM was observed, MAF from the PF group showed an approximate 35% increase of phagocytic ability compared to the supernatant of splenic cells cultured with medium only. However, MAF from the DEF group had no effect on phagocytosis. These results suggest that pyridoxine deficiency affects not only phagocytic function of AM responsible for host defense in the lung but also MAF production by splenic cells.     

Changes of alveolar macrophages in protein-deficient rats

Protein malnutrition was achieved by feeding female F344 rats a 5% casein diet for 7 weeks. At appropriate times, animals were killed and their alveolar macrophages (AM) were obtained by broncho-pulmonary lavage of the lung. Functional changes of AM were determined by measuring phagocytosis of latex beads, yeast cells or opsonized sheep red blood cells (SRBC) and the ability to respond to a macrophage-activating factor (MAF) such as lymphokines. After 3 weeks on a low casein diet, the number of AM was much lower than in rats on control diet, but the abilities of the AM to phagocytose latex and yeast cells were the same as those of controls. Phagocytosis of opsonized SRBC was higher than in control rats but could not be enhanced by in vitro treatment with MAF. The most striking ultrastructural feature of these AM was the abundance of finger-like microvilli on the cell surface before phagocytosis; after ingestion of SRBC into phagocytic vacuoles there were only a few short microvilli on the surface. These data suggest that dietary protein malnutrition affects the number and phagocytic functions of AM responsible for host defense in the lung.     

Effects of dietary restriction on cellular immunity in rats

Phagocytosis of opsonized sheep red blood cells (SRBC) by alveolar macrophages (AM) was measured in rats fasted for 1 to 9 days or fed on diets restricted 20 to 95% compared to control group for 2 and 8 weeks. In rats fasted for 1 to 6 days, AM showed an increased phagocytosis at 2 days after fasting, but their phagocytic activity remarkably decreased afterwards. Furthermore, phagocytic activity of AM per rat revealed much more decrease at 3 to 6 days after fasting. Then the production of interleukin-1 (IL-1) by AM increased with prolonged fasting, but the production of prostaglandin E2 (PGE2) by AM cultured with lipopolysaccharide (LPS) conversely decreased in rats fasted for 2 days or longer. The proliferation of splenocytes increased with prolonged fasting. On the other hand, 20 to 95% restricted diets induced the increased phagocytosis of AM with prolonged experimental period. However, phagocytic activity of AM per rat showed significant increase only in rats on a 40% restricted diet. The findings suggest that differences in both duration and degree of dietary restriction modulate phagocytic function of AM, and may contribute to explaining, in part, conflicting observations which have been obtained on the immunologic state in malnourished animals.     

母鼠妊娠前慢性不可预见性应激对子代学习记忆能力及海马突触结合蛋白I和突触结合蛋白IV表达的影响

目的 探讨母鼠妊娠前慢性不可预见性应激(chronic unpredictable stress,CUS)对1月龄子鼠学习记忆能力及大脑海马突触结合蛋白 I(synaptotagmin I,syt I)和突触结合蛋白 IV(syt IV)表达的影响。方法 SD系成年健康雌性大鼠随机分为正常对照组(8只)和CUS组(10只);采用11种刺激方法构建CUS模型;子鼠1月龄时行Morris水迷宫试验;应用Elisa法检测实验动物血清的皮质醇(cortisol,COR)和促肾上腺皮质激素释放激素(corticotropin-releasing hormone,CRH)水平;采用免疫组织化学法检测子鼠大脑海马syt I和syt IV的表达情况。 结果 1)应激结束时和分娩后,CUS组母鼠血清CRH和COR水平均高于正常对照组。2)水迷宫实验中,CUS组子鼠寻找平台潜伏期长于正常对照组子鼠,而穿越平台次数少于正常对照组子鼠,差异有统计学意义。3)1月龄CUS组子代CRH和COR水平均高于正常组子代。4)CUS组和正常对照组子鼠大脑海马syt I和syt IV蛋白表达的平均光密度(MOD)值,只在CA3层和DG层差异均有统计学意义。 结论 母鼠妊娠前CUS会使子鼠的学习记忆能力下降,并使大脑海马syt I和syt IV的表达减少。     

Influences of an infusion of lipid emulsion on phagocytotic activity of cultured Kupffer's cells in septic rats

An experimental study was undertaken to study the influences of an infusion of lipid emulsion on phagocytosis of Kupffer's cells in septic rats. Sepsis was induced in 13 rats by ligating the cecum. Five of them received glucose as the sole nonprotein calorie (septic-glucose group), four of the rats received 25% of the nonprotein calorie with lipid emulsion, Intralipid (septic-lipid group), and the remaining four rats did not receive any intravenous solution and were allowed access to water (septic-fasted group). Another four rats which received neither intravenous solution nor ligation of the cecum served as the control group. The intravenous infusion was carried out for 72 hr. The phagocytotic activity of Kupffer's cells was determined by the ability to engulf latex particles with a size of 1.09 micron, in vitro. The phagocytotic activity was enhanced by the presence of sepsis but it was inhibited by starvation. The difference in the phagocytotic activity between the septic-glucose group and the septic-lipid group was not significant. These results suggest that, insofar as an in vitro study is concerned, a 72-hr infusion of lipid emulsion at a rate of 25% of the total nonprotein calorie does not influence the phagocytotic activity of cultured Kupffer's cell obtained from septic rats.     

High dietary intakes of vitamin E and cellular immune functions in rats

High dietary intakes (100-2500 mg/kg diet) of vitamin E (dl-alpha-tocopheryl acetate) modified the functions of splenic lymphocytes and alveolar macrophages (AM). The numbers of splenocytes and AM obtained from male F344 rats fed high vitamin E diets significantly increased at 10 d after the onset of the experiment. Splenic lymphocytes' responses to concanavalin A and natural killer cell activity also increased with increasing contents of vitamin E in the diets. Furthermore, the ability of AM to phagocytose opsonized sheep red blood cells increased with increasing contents of vitamin E in diets and showed a fivefold increase in rats fed the diet with the highest vitamin E content (2500 mg/kg diet) compared with rats in the control group. The lavage fluid of lungs from rats fed a high vitamin E diet (500 mg/kg diet) increased phagocytic activity of AM from rats fed a basal diet; it also induced a 72% increase in activity compared to that in control rats. The phagocytic activity of AM was not enhanced when the large molecules (MW greater than 10,000) were removed by ultrafiltration from the lavage fluid of lungs of rats fed the high vitamin E diet (500 mg/kg diet). These data suggest that there is macrophage-activating factor-like material in the lavage fluid of lungs of rats fed high vitamin E diets and that high vitamin E diets may activate not only splenic lymphocytes but also AM.     

Amino acids and indoleamines in the brain after infusion of branched-chain amino acids to rats with liver ischemia

Rats with a portacaval anastomosis and ligation of the hepatic artery 2 days later were infused for 6 hr with a 10% glucose solution (group I) or the same solution combined with 0.24 M/liter branched-chain amino acids (BCAA, group II). Control animals with portacaval anastomosis and sham-operation (group III) or two sham-operations (group IV) were infused with a 10% glucose solution. The rats were killed by decapitation and indoleamines and amino acids were determined in the brain. Rats with liver ischemia were stuporous at the end of the experiment irrespective of treatment. The concentrations in the cortex of lysine, methionine, phenylalanine, threonine, alanine, glutamine, glycine, histidine, and tyrosine were significantly increased in group I compared to group IV. Infusion of BCAA to rats with liver-ischemia (group II) resulted in significantly lower concentrations of lysine, methionine, phenylalanine, threonine, histidine and tyrosine and increased concentrations of isoleucine, leucine, valine, and arginine compared to group I. The content of serotonin in the cortex and brain stem was significantly increased in group I compared with the BCAA-treated animals (group II) and the control groups III and IV. The concentrations of 5-hydroxyindoleacetic acid (5-HIAA) in the cortex and brain stem were higher in group I than in group IV. Infusion of BCAA to rats with liver ischemia normalized the concentrations of 5-HIAA in the cortex and brain stem.     

Ingested aggregates of ultrafine carbon particles and interferon-gamma impair rat alveolar macrophage function

Alveolar macrophages (AM), obtained by lavage from the rat lung, were allowed to ingest aggregated ultrafine carbon particles, about 1 microgram/10(6) AM, which is a realistic result of long-term exposure to ambient air. The effects of the ingested carbon on the phagocytosis of test particles and oxidative metabolism of the AM were studied. In addition, the effects of short-term (40 min or 2 h) and long-term (28 or 44 h) incubation with interferon gamma (IFN-gamma) on AM loaded and unloaded with carbon were investigated. Phagocytic activity was studied using fluorescein-labeled 3.2-microgram silica particles. The attachment and ingestion processes were evaluated separately. The ingested carbon markedly impaired the phagocytosis of silica particles; the accumulated attachment (sum of attached and ingested particles per AM) decreased from 5.0 to 4.2 particles/AM and the ingested fraction (number of ingested particles per AM divided with accumulated attachment) from 0.42 to 0.27. The short-term incubation with IFN-gamma tended to increase the accumulated attachment (from 5.0 to 5.7 particles/AM) and decreased the ingested fraction (from 0.42 to 0.34) in unloaded AM. Long-term incubation with IFN-gamma markedly impaired both the accumulated attachment (to 3.8 particles/AM) and the ingested fraction (to 0.24) in unloaded AM and the carbon load further decreased the accumulated attachment to 2.8 particles/AM, and the ingested fraction to 0.21. The oxidative metabolism was not effected by the ingested carbon or the short-term incubation with IFN-gamma, but the long-term incubation with IFN-gamma increased it with a factor of almost 3. Our results suggest that ingested environmental particles in AM may markedly impair their phagocytic capacity, especially during long-term exposure to IFN-gamma as after infections, and there might be an increased risk for additional infections. Moreover, during an episode of high ambient particle concentration the inhaled particles will not be efficiently phagocytized and may thereby damage the Lung tissue.     

边缘VA缺乏对大鼠胚胎骨骼发育及视黄酸受体表达的影响

目的研究边缘性维生素A(VA)缺乏及补充对大鼠胚胎骨骼发育的影响,及其与视黄酸受体(RARs)基因表达的关联性。方法初断乳SD雌性大鼠30只,按体重随机分为边缘性VA缺乏组(AM),边缘性VA缺乏妊娠0d(E0d)补充组(AS)和正常对照组(AN)。AM和AS组喂饲边缘性VA缺乏饲料(含VA0.4IU/gdiet),AN组喂饲VA充足饲料(含VA4IU/gdiet)。60d后与正常雄鼠交配。AS组自E0起改喂VA补充饲料(含VA10IU/gdiet)。于E12.5d和E19.5d将孕鼠处死,取胚胎。观测E19.5d胚胎骨骼发育指标;用荧光定量PCR及Westernblot检测E12.5d胚胎组织视黄酸受体的表达。结果AM组97.2%的E19.5d胚胎骨骼发育明显迟缓并出现多种骨骼畸形;E12.5d胚胎RARβ、RARγ表达水平明显下降。AS组胚胎各指标较AN组无异。结论视黄酸受体参与介导边缘性VA缺乏导致的大鼠胚胎骨骼发育异常,孕早期补充VA可有效预防骨骼畸形的发生。     

Infusion of a branched-chain amino acid-enriched solution and alpha-ketoisocaproic acid in septic rats: effects on nitrogen balance and skeletal muscle protein turnover

Sepsis was induced by cecal ligation and puncture in male Sprague-Dawley rats weighing approximately 70 g and the animals were intravenously infused with one of four isocaloric solutions: group I (N = 16), 8.5% dextrose solution; group II (N = 16), alpha-ketoisocaproic acid (KIA, 5.1 mg/ml) in 8.5% dextrose; group III (N = 16), FreAmine HBC (containing 45% branched-chain amino acids) in 2.5% dextrose; and group IV (N = 17), FreAmine HBC in 2.5% dextrose + KIA (5.1 mg/ml). Eighteen hr after induction of sepsis, extensor digitorum longus (EDL) and soleus (SOL) muscles were dissected with intact tendons and incubated for the study of protein synthesis and degradation, which were measured as incorporation of 14C-phenylalanine into protein and release of tyrosine into incubation medium, respectively. Urine was collected for determination of nitrogen balance. Nitrogen balance, which was equally negative in groups I and II, was significantly improved in groups III and IV and became equally positive in these groups. Protein synthesis and degradation rates in incubated EDL and SOL muscles were similar to those which we have reported previously in septic rats. Except for a higher synthetic rate in SOL in group II, no other differences in protein synthesis or degradation rates between the four experimental groups were found. Thus, the present study showed that infusion of a branched-chain amino acid-enriched solution improved nitrogen balance in septic rats. KIA alone or administered with the amino acid solution did not affect nitrogen balance.(ABSTRACT TRUNCATED AT 250 WORDS)     

Randomized structured triglycerides increase lymphatic absorption of tocopherol and retinol compared with the equivalent physical mixture in a rat model of fat malabsorption

Previously we demonstrated that the digestion, absorption and lymphatic transport of lipid and key essential fatty acids (EFA) from randomly interesterified fish oil/medium-chain structured triglycerides (STG) were significantly higher than an equivalent physical mixture (PM) in a normal lymph fistula rat model and in a rat model of lipid malabsorption caused by ischemia/reperfusion (I/R) injury. The goals of this study were to further explore the potential absorptive benefits of STG by comparing the intestinal absorption and lymphatic transport of tocopherol and retinol when delivered gastrically with either STG or PM under normal conditions and after I/R injury to the small bowel. Food-deprived male Sprague-Dawley rats were randomly assigned to two treatments (sham controls or I/R). Under halothane anesthesia, the superior mesenteric artery (SMA) was occluded for 20 min and then reperfused in I/R rats. The SMA was isolated but not occluded in control rats. In both groups, the mesenteric lymph duct was cannulated and a gastric tube was inserted. Each treatment group received 1 mL of the fish oil/MCT STG or PM (7 rats/group) along with (14)C-alpha-tocopherol and (3)H-retinol through the gastric tube followed by an infusion of PBS at 3 mL/h for 8 h. Lymph was collected hourly for 8 h. Under steady-state conditions, the amount of (14)C-alpha-tocopherol and (3)H-retinol transported into lymph was significantly higher in the STG-fed rats compared with those fed PM in both control and I/R groups. In addition, control and I/R rats given STG had earlier steady-state outputs of (14)C-alpha-tocopherol and (3)H-retinol and maintained approximately 30% higher outputs in lymph throughout the 8-h lymph collection period compared with rats given the PM. We conclude that STG provides the opportunity to potentiate improved absorption of fat-soluble vitamins under normal and malabsorptive states.     

Decreased phagocytosis and superoxide anion production in alveolar macrophages of rats exposed to nitrogen dioxide

Effects of nitrogen dioxide (NO₂) on pulmonary defense systems were investigated by determining phagocytosis and Superoxide anion (O ₂ ^– ) production by alveolar macrophages (AM) of rats. Rats were exposed to 8 ppm NO₂ for 1 to 7 days and 4 ppm NO₂ for 1 to 10 days, respectively. The phagocytic activity of AM was determined by taking yeast particles into the cells. The O ₂ ^– production by AM was determined at rest during phagocytosis of zymosan particles and stimulation with phorbol myristate acetate (PMA). The suppression of phagocytosis of AM was observed in cells from rats exposed to 8 ppm NO₂ for 5 and 7 days. The suppression was also shown in AM from rats exposed to 4 ppm NO₂ for 7 days. There were remarkable decreases in the O ₂ ^– production by AM from 8 ppm NO₂-exposed rats at rest during zymosan phagocytosis and PMA stimulation on and after day 3. The O ₂ ^– production by AM from 4 ppm NO₂-exposed rats at rest and during zymosan phagocytosis decreased on days 3, 5, and 10, but remained unchanged on day 7. The O ₂ ^– production by PMA-stimulated AM from 4 ppm NO₂-exposed rats decreased on day 3. The results suggest that such diminution in phagocytosis and O ₂ ^– production by AM from NO₂-exposed rats demonstrated the adverse effects on the pulmonary early defense systems and potentially causes bacterial infections.     

Differential responses of rat alveolar and peritoneal macrophages to man-made vitreous fibers in vitro

Different approaches, including inhalation and intraperitoneal injection assays, have been used to assess the potential health effects of man-made vitreous fibers (MMVF). The purpose of this study was to compare the phagocytic activity and the formation of reactive oxygen species by rat alveolar macrophages (AM) and peritoneal macrophages (PM) upon exposure to MMVF10 glass wool and MMVF21 rock wool fibers. Macrophage (Mphi) phagocytosis of mineral fibers was assessed by optical videomicroscopy and computer-aided image analysis. Mphi were classified as cells not associated with fibers, cells with attached fibers, cells with incompletely phagocytized fibers (an appearance known as "frustrated phagocytosis"), and cells with completely phagocytized fibers. The production of superoxide anions by AM and PM upon incubation with MMVF10 and MMVF21 fibers was determined by the superoxide dismutase-inhibitable reduction of ferricytochrome C. PM were found to have a lower phagocytic activity than AM. A significantly higher percentage of AM than of PM underwent frustrated phagocytosis of MMVF10 and MMVF21 fibers. In line with these findings, AM generated higher levels of oxygen radicals than PM upon exposure to MMVF21 fibers. In contrast, MMVF10 fibers failed to induce the generation of reactive oxygen species by both AM and PM. Our in vitro results show that the phagocytic activity, in particular the frustrated phagocytosis of mineral fibers, was significantly lower in PM than in AM. The data support the idea that the durability and biopersistence of mineral fibers are higher in the peritoneal cavity than in the lung.     

锌抗煤尘肺组织细胞毒性的实验研究

本文采用大鼠短期体内试验方法,研究了锌对煤尘肺组织细胞毒性的拮抗作用。实验结果表明,锌可降低染煤尘大鼠BALF(支气管肺泡灌洗液)中的细胞总数、PMN(多形核中性粒细胞)数,LDH(乳酸脱氢酶)活性及蛋白质浓度,提高细胞存活率及AM(肺泡巨噬细胞)的吞噬功能,提示锌具有抑制肺内由该煤尘所致的炎症反应及细胞损伤,增强细胞活性及功能等作用,证明锌可拮抗该煤尘的细胞毒性,从而对大鼠肺组织细胞起保护作用。上述实验结果,不仅加深了锌与煤尘危害作用关系的认识,同时为进一步研究锌在煤工尘肺防治中的应用提供了一定的实验依据。     

Differential effects of fish oil and folic acid supplementation during pregnancy in rats on cognitive performance and serum glucose in their offspring

OBJECTIVE: We studied the effect of folic acid and polyunsaturated fatty acid supplementation during pregnancy in Wistar albino rats on cognitive performance and serum glucose concentrations in their pups. METHODS: Pregnant female rats from four groups (n = 6/group) were fed casein diets with 18% protein and 2 mg of folic acid/kg of diet (group I), 12% protein and no folic acid (group II), 12% protein and 8 mg of folic acid/kg of diet (group III), or 12% protein and 70 g of cod liver oil/kg of diet (group IV). All pups were weaned on standard control diet with 18% protein. Cognitive performance, brain fatty acid profile, and serum glucose concentrations were studied in offspring at age 6 mo. RESULTS: There was no significant difference in length of gestation or litter size, but the litter weight for group IV was lower (P = 0.047) than that for group I. After weaning, males in group II had lower (P < 0.05) body weights, but those in group III had weights comparable to those in group I for both sexes. In group IV, body weights were lower beyond 15 wk (P < 0.05). Relative brain weight and cognitive performance were significantly higher (P < 0.05) in group IV males and showed higher levels of brain gamma-linolenic acid. Further, these animals had serum glucose levels comparable to those of control animals at age 6 mo, whereas serum glucose levels were higher in males from groups II (P = 0.01) and III (P = 0.01). CONCLUSION: Fish oil supplementation during pregnancy improved cognitive performance and maintained glucose levels into adulthood, unlike folic acid supplementation, which supported only fetal growth and did not maintain glucose levels.     

Effect of continuous and discontinuous intravenous or intragastric total parenteral nutrition in rats on serum lipids, liver lipids and liver lipogenic rates

Lipogenesis and evidence of fat accumulation in the liver were investigated in adult male rats fed a hypertonic dextrose diet by continuous (C) and discontinuous (D) intravenous (IV) or intragastric (IG) infusion for 14 d. Rats fed by the IV and IG route were infused continuously and discontinuously (2100-0900) with 55 ml/d of a solution containing 30% dextrose and 2.72% amino acids plus vitamins and minerals. An orally (Or) fed group was fed 21.2 g of a solid diet, which provided an equivalent amount of calories and nitrogen as the infusion diet. Serum lipids, glucose, and insulin levels, de novo fatty acid synthesis in adipose tissue and liver, and the content of liver lipids were not altered by feeding the diet IV or IG. De novo lipogenesis was elevated in the livers of the continuously and discontinuously infused IV-or IG-fed rats compared with Or-fed rats. Fat accumulated in the livers of the rats infused continuously but not in the livers of the rats fed DIV, DIG or Or. Discontinuous feeding was associated with the mobilization of fatty acids that are necessary for lipoprotein formation and transport from the liver, which may explain, in part, why discontinuously infused rats do not develop fatty livers. These data indicate that cycling the total parenteral infusion may have clinical importance.     

Glutamine infusion during ischemia is detrimental in a murine gut ischemia/reperfusion model

BACKGROUND: Gut ischemia/reperfusion (I/R) frequently occurs in clinical settings as a result of disproportionate splanchnic hypoperfusion during shock. Glutamine (GLN) supplementation of total parenteral nutrition (TPN) before gut I/R improves survival after gut I/R compared with standard TPN. However, it is unknown whether GLN treatment after the occurrence of the insult is beneficial or not. The aims of this study were to examine effects of GLN infusion during gut ischemia on survival, myeloid cell (neutrophils + monocytes) activation, and vascular permeability in organs. METHODS: Male Institute of Cancer Research (ICR) mice were randomized to control and GLN groups. After IV cannulation, mice underwent 90 (experiments 1 and 2) or 60 (experiment 3) minutes of gut I/R. Control mice received normal saline infusion at 1 mL/h for 60 minutes during ischemia, whereas the GLN group was given 3% GLN solution. In experiment 1, survival rates were monitored for 72 hours (n = 25). In experiment 2, peripheral blood was obtained at 2 or 4 hours after reperfusion (n = 17). Reactive oxygen intermediate (ROI) production by myeloid cells was determined by flow cytometry using dihydrorhodamine 123 with or without phorbol myristate acetate stimulation. Expression of CD11a and CD11b on myeloid cells was also measured. Myeloperoxidase (MPO) activity in the lung was evaluated. In experiment 3, vascular permeability in organs was measured using Evans blue at 2 or 4 hours. RESULTS: In experiment 1, survival time in the GLN group was significantly reduced compared with the control group (p = .02, log-rank test). The survival rates were 92% (12/13) and 42% (5/12) for the control and GLN groups at 12 hours (p = .01) and 38% (5/13) and 0% (0/12) at 48 hours (p = .02), respectively. In experiment 2, ROI production was significantly higher in the GLN group than in the control group after PMA stimulation both at 2 and 4 hours. CD11b expression was significantly higher in the GLN group than in the control group at 4 hours. There was no difference in pulmonary MPO activity at either time point. In experiment 3, GLN infusion significantly increased hepatic vascular permeability compared with saline infusion at 4 hours. CONCLUSIONS: GLN infusion during ischemia is detrimental for survival after gut I/R. A possible mechanism is excessive priming of myeloid cells caused by GLN infusion. Timing of GLN administration is critical for outcome after gut ischemic insult.     

Effects of soluble fiber on matrix metalloproteinase-2 activity and healing of colon anastomosis in rats given radiotherapy

BACKGROUND AND AIMS: Soluble fiber is fermented by colonic microflora yielding short-chain fatty acids (SCFAs) in the colon. We aimed to investigate the effect of oral administration of soluble fiber on healing of anastomosis and matrix metalloproteinase-2 activity in radiotherapy received colonic anastomosis. METHOD: Eighty-four Wistar rats were divided into six groups. All rats were performed a left colonic resection with end-to-end anastomosis. Group I received rat cow. Group II received soluble fiber orally for five consecutive days preoperatively as well as 3rd and 6th days postoperatively. Group III received SCFAs via rectum for five consecutive days preoperatively. Group IV received irradiation to the pelvis at a total dose of 24 Gy on the 10th and 5th days before the operation. Group V was exposed to irradiation like the rats in Group IV and oral treatment like the rats in Group II. Group VI received irradiation like the rats in Group IV and transrectal treatment like the rats in Group III. On the 3rd and 7th postoperative days, all the rats were anesthetized to evaluate the anastomosis healing clinically, histologically and biochemically. RESULTS: Third and 7th day bursting pressures of the rats that were fed with a normal diet and exposed to radiotherapy were significantly decreased (P<0.001). Bursting pressures of Groups V and VI on the 7th day were significantly higher than the control group's bursting pressures (P<0.05). Hydroxyproline levels of Group IV were significantly decreased (P<0.001). Following oral soluble fiber and transrectal administration of SCFAs, these low levels reached to the levels of control radiotherapy group. Matrix metalloproteinase-2 activity of all the rats that were exposed to radiotherapy was higher than the control group (P<0.001). Matrix metalloproteinase-2 enzyme levels in the Groups V and VI were lower than the ones in the Group IV (P<0.001). The histologic parameters of anastomotic healing such as epithelial regeneration, exudate, necrosis, and fibroblast levels were significantly improved by the use of oral soluble fiber and transrectal SCFAs treatment. CONCLUSION: Undesirable effects of preoperative radiotherapy on mechanical, histological and biochemical parameters can be overcome by oral soluble fiber. Oral soluble fiber administration has similar positive effects like the transrectal administration of the SCFA's.     

Ultrastructural changes of alveolar macrophages of protein-deficient rats

Enhancement of phagocytosis of alveolar macrophages (AM) was examined by cytochemical and electron microscopic studies on macrophages from protein-deficient rats. The macrophages from rats fed on 5% casein diet had longer microvilli, more phagocytic vacuoles and more lysosomes with acid phosphatase activity than those from control rats. Many phagocytic vacuoles were seen close to the site of attachment of opsonized sheep red blood cells (SRBC) and were mainly located in the subplasmalemmal layer which was rich in microfilaments but contained few cytoplasmic organelles. After attachment, opsonized SRBC were engulfed through a hemispherical crater into the phagocytic vacuoles. The phagocytic vacuoles seemed to be formed by invagination of the cell surface because they had membrane ATPase activity continuous with that of the outer surface of the plasma membrane. In the cell, the vacuoles fused with the numerous preexisting lysosomes in the interior of the cell receiving the contents of the latter. The mechanism of enhancement of phagocytosis in protein-deficiency is discussed.